The subject matter disclosed herein relates to an article including a weld joint and, more particularly, to an article including first and second annular parts and an annular weld joint.
Weld joints are often used in various industrial applications to couple one part to another part. Compressor in an aircraft cabin air compressor is one such application in which weld joints are employed. The assembly includes a wrought annular part that is welded to a cast annular part in a hybrid configuration. The hybrid configuration is used because, while the wrought annular part is often provided in a relatively simple shape, the cast part may be provided in with a more complex geometry that would be difficult to form without casting.
With the hybrid configuration, the weld joint is formed by an electron beam (EB) weld process that has been found to be effective at coupling wrought parts with cast parts such that the weld joint is integrally strengthened. Generally, EB welding is achieved by aiming a very small stream of electrons at the location where the EB weld joint is desired. This allows the EB weld joint to form while minimizing a size of the heat affected zone (HAZ) adjacent to the weld. By keeping the size of the HAZ small, a number of defects in the cast part can also be minimized.
Although the EB welding process can be effective in forming relatively thin EB weld joints with few defects in the cast part, it has been found that EB weld joints tend to form increased numbers of defects in cast parts for relatively thick joints where significant heat and large HAZs are generated. Typically, this observation led researchers to design the mirrored hybrid configuration of FIG. 1 in which the wrought part 1 has a protrusion 2, which is welded to an end 3 of the cast part 4. As shown in FIG. 1, the corresponding angles, α1 and α2, are mirrored such that a thickness of the end 3 is limited to the thickness of the protrusion 2. Nevertheless, excessive numbers of defects are still typically found in the cast part 4 due to stresses incurred in the welding process and it is often necessary to replace the cast part 4 during servicing.